1. Field of the Invention
The present invention relates to cameras of the type having a lens carrier member that is movable selectively to either of two alternate positions to change a parameter of the camera's optical system, and more particularly to a damper device for cushioning the movement of the lens carrier member into contact with two abutment surfaces that establish its alternate positions.
2. Description of the Prior Art
It is well known in the prior art to provide a camera with a lens carrier member that is movable selectively to either of two positions to change a parameter of the camera's optical system. For example, U.S. Pat. No. 3,882,520 discloses a representative camera having a primary lens and a secondary lens that is movable into and out of alignment with the primary lens to change the effective focal length of the camera's objective lens system. Similarly, as also shown in that reference, it is known to move a lens element in the viewfinder between two predetermined alternate positions to change the field of view provided by the viewfinder. Referring still to that reference, the objective lens 24 is moved laterally of its optical axis between two positions defined by abutment members 26 and 28 and the viewfinder lens element 74 is moved along its optical axis to either of two positions defined by abutment members 70 and 72. As is typical in many such arrangements, the movable lens carrier means shown and described in that reference are urged into contact with the appropriate abutment members by a bidirectionally operable toggle spring 50 that biases the lens carrier members in the directions of their respective movements during the final portions of their movement to their selected operative positions. Because the spring means by which the carrier members are biased against the corresponding abutment members must be quite strong to insure proper positioning of the respective lenses, the lens carriers abut against the stop members with considerable impact. This impact produces objectionable noise when the lenses are adjusted to their alternate positions and also tends to produce mechanical shocks and vibrations that may damage the camera mechanism.